The invention relates to a method for the manufacture of a pack of coated metal laminas for electrical machinery and appliances in which the laminas are punched out, arranged at a distance from one another, exposed in an annealing furnace to a reducing gaseous atmosphere, and then assembled in the final plate-pack form.
The well-known process (see German patent DE-AS No. 14 33 774) for manufacturing rotor and stator plates for electrical machinery by means of annealing in a reducing atmosphere after the plates have been punched includes stamping stator or rotor plates out of a steel plate with higher electrical losses than are present in ordinary dynamo plates of a hardness suitable for stamping purposes, placing them in a continuous furnace where they are hung on rods in a reducing atmosphere of about 800.degree. C., and subsequently cooling them to about 550.degree. to 650.degree. C. They are then provided at this temperature, in an oxidizing gaseous atmosphere, with an insulating overlay; next the plates that have been electrically upgraded in this manner are coated, pressed together with plane-parallel faces, and fastened in place, for example by rivets, screws or welding, according to a predetermined plate-pack index, such as the number of laminas per pack, or the weight or height of the pack.
A method is also already known (e.g. U.S. Pat. No. 3,202,851) for providing the metal laminas, when they are punched out, with projections or depressions corresponding to one another, by means of which the individual laminas of a pack can be pressed together into a solid unit, since the projections of one plate hook into the depressions of the other plate that is pressed onto it, with mutual positive or non-positive locking, as the case may be.
Another process (e.g. German patent DE-GM No. 18 82 073) is to insert, when the laminas are being coated, at least one plate each time until the predetermined height of the plate-pack is reached. In this case each plate has instead of a projection, only an enlarged hole so that the plates adjacent to this intermediate plate do not hook into one another, and, in a packing device, the plate-packs can be automatically separated after their predetermined size has been achieved.